Video Resizer for Social Media
Fit a video to the shape every platform asks for — with a tasteful blurred background.
Shape and fit
What will happen
About the Video Resizer for Social Media
Change a video to the shape a platform expects: 1080 × 1920 for Reels, Shorts and TikTok, 1920 × 1080 for YouTube landscape, 1080 × 1080 for a square post, 1080 × 1350 for a 4:5 post, 720 × 1280 for a lighter WhatsApp Status, 1200 × 1200 for LinkedIn and 1280 × 720 for X. Or type your own width and height — any size from 16 px to 7680 px.
When the shape does not match the video, pick what fills the bars. Fit on a blurred copy keeps the whole picture over a soft blurred background made from the picture itself (the Instagram look). Fit on a colour keeps the whole picture over a flat colour. Fill scales the picture to fill the shape and crops what sticks out. Stretch squashes it to fit — never nice, but useful for test footage.
The sound is copied without re-encoding; only the picture is written again, by this browser’s video encoder.
How to use it
- Drop a video on the box or click Choose a video. MP4, MOV, M4V, MKV, WebM, MPEG-TS and 3GP are all read.
- Pick a shape — Reels, YouTube, Instagram square or 4:5, WhatsApp Status, LinkedIn, X, 720p — or set your own width and height. The preview redraws at once, so you can see the bars or the crop before you export.
- Choose how to fit the picture into the shape: on a blurred background, on a colour, filling (cropped) or stretched.
- Press Resize the video and Download the file.
Examples
1920 × 1080 MP4, 1:20 · Reels (9:16) · Fit on a blurred copy
1080 × 1920 MP4, 1:20 — the whole clip across the middle of the screen, with a soft blurred version of it above and below, sound copied
1920 × 1080 clip · Instagram square (1:1) · Fill
1080 × 1080 MP4 centred on the middle of the frame; the left and right sides are left out
1080 × 1920 clip filmed on a phone · WhatsApp Status (9:16) at 720 × 1280
720 × 1280 MP4 — smaller, still 9:16, faster to upload
How each fit works
- Fit on a blurred copy keeps the whole picture, as large as the shape allows, in the middle of the frame; above and below (or left and right) it fills the bars with a blurred, slightly darkened copy of the picture, so nothing of your clip is lost and the frame still looks like it belongs together. It is the look most vertical posts made from a landscape clip use.
- Fit on a colour does the same but fills the bars with the colour you choose. Black is the usual safe choice; brand colours let the frame match your post.
- Fill scales the picture so it covers the whole shape and crops what sticks out, like the Instagram "fill" button. The subject must stay in the middle: nothing picks the subject out of the frame automatically.
- Stretch scales the picture to the shape without keeping its proportions. Shapes in it look squashed, so it is useful for test footage only.
Which sizes the platforms publish
Only some of these numbers come from a platform’s own help pages, so the page says which:
- YouTube lists its 16:9 resolutions, including 1920 × 1080 (1080p) and 1280 × 720 (720p): recommended upload encoding settings. Shorts are vertical and go up to 1080p: create a Short.
- LinkedIn accepts 256 × 144 up to 4096 × 2304 with an aspect ratio between 1:2.4 and 2.4:1, and names no recommended size: video specifications. The 1200 × 1200 preset is a square inside that range.
- Instagram, TikTok and WhatsApp Status publish no pixel size in their help pages. 1080 × 1920, 1080 × 1080, 1080 × 1350 and 720 × 1280 are the standard sizes for those shapes, which is why every preset stays editable: type the width and height you have been given and the tool uses it.
Whatever you upload, the platform re-encodes it on its servers, so a file larger than its playback size does not improve what people see — it only takes longer to upload.
Why the sound is untouched
A video file is a container with the picture and the sound in separate streams. Resizing changes the picture only, so the sound is copied packet for packet, exactly as it is. No audio quality is lost, and the file is written in seconds for a long video, because nothing is decoded.
Quality and format
The picture is encoded in the same container as your input (MP4, MOV, MKV or WebM) with a codec this browser can encode — H.264 by default, which plays everywhere. Choose Very high quality to keep the smallest loss, or Smaller file to save disk space.
Sizes are rounded to even numbers because H.264 and most other codecs store colour at half the resolution of brightness and need even sides.
Limitations
- Needs WebCodecs (current Chrome, Edge, Safari or desktop Firefox) and a decoder for the video’s codec; HEVC needs a hardware decoder in the browser.
- No subject tracking: the fill crop keeps the middle of the frame; crop the picture yourself first with the Video Cropper if the subject is off-centre.
- The blurred background is made from the picture itself, so a very dark or very bright clip gives a very dark or bright background. Choose Fit on a colour for a flat frame.
- HDR video is converted to standard dynamic range when re-encoded, and subtitle tracks and chapters are not carried over.
- Sizes are rounded to even numbers; a typed odd value is nudged by 1 px.
- Only the main video track is kept; extra video tracks are left out.
Privacy
Everything happens in your browser. What you enter or open here is not uploaded or stored by MySmartCoPilot.
Frequently asked questions
What is the right size for Reels / Shorts / TikTok?
1080 × 1920 — a 9:16 vertical video. The Reels, Shorts & TikTok preset gives exactly that.
Which background looks best under a vertical clip?
A blurred copy of the picture itself usually looks the most finished, because the bars carry the clip’s own colours. A flat colour (black, white or your brand colour) is cleaner for a logo clip or a screen recording.
What is the difference between fit and fill?
Fit keeps the whole picture and adds bars. Fill keeps no bars but crops the picture to fill the shape. Stretch keeps no bars and no crop, at the cost of distortion.
Will the result upload well to Instagram or TikTok?
Yes. The presets are the standard sizes for each shape, and where a platform publishes its own numbers the page says so (see Which sizes the platforms publish). If you have been given a different size, type it in the width and height boxes.
Does resizing lower the quality?
The picture is encoded again, which loses a little detail like any export. The sound is not re-encoded. Pick Very high quality to keep the loss smallest.
Is my video uploaded?
No. It is decoded, repainted at the new size and encoded inside your browser; the result is saved to your device.